<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      padding: 0;
      margin: 0;
    }
    .cotainer {
      width: 100vw;
      height: 100vh;
      background-color: aliceblue;
    }
    .box {
      width: 300px;
      height: 200px;
      background-color: antiquewhite;
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      margin: auto;
      animation: boxAnimation 3s infinite;
      transition: background-color 3s;
    }
    @keyframes boxAnimation {
      0% {
        transform: translateX(0);
      }
      50% {
        transform: translateX(100px);
      }
      100% {
        transform: translateX(-100px);
      }
    }
    .box:hover {
      background-color: aquamarine;
    }
    .wrapper {
      height: 400px;
      background-color: aqua;
      margin-top: 40px;
      overflow: hidden;
    }
    .box1 {
      height: 200px;
      margin-top: 50px;
      background-color: bisque;
    }
  </style>
</head>
<body>
  <div class="cotainer">
    <div class="wrapper">
      <div class="box1"></div>
    </div>
    <div class="box"></div>
    <a download="第一个文件" href="http://localhost:8080/test.md">下载</a>
  </div>
</body>
</html>